Construction began Monday on the nation's largest transportation project, an $8.7 billion rail tunnel under the Hudson River, that could speed the ride to work for commuters in the Hudson Valley.

The new tunnel, which is expected to take eight years to construct, will double the amount of trains that travel into New York City.

Traveling into New York City from places such as Pearl River usually means getting off somewhere in New Jersey to take another train under the Hudson River. But when the tunnel is completed, commuters from Rockland and Orange that use New Jersey Transit won't need a transfer to get into the city.

The Obama administration will provide $3 billion toward the $8.7 billion project.